What anatomical feature connects the proximal humerus to the proximal radius and ulna?

The anatomical feature that connects the proximal humerus to the proximal radius and ulna is best described by a type of joint that allows for significant movement in one plane. In this case, the correct choice refers to a hinge joint, which is characterized by its ability to permit flexion and extension.

In the context of the elbow joint, which includes the interaction of the proximal humerus with the proximal radius and ulna, the hinge joint structure allows for the bending and straightening of the arm—essential movements necessary for various activities such as lifting, throwing, or waving. The articular surfaces of the bones are shaped to facilitate this motion, providing stability while allowing for a wide range of functional movement.

Other joint types, like a ball-and-socket joint, allow for multi-directional movement but are not the primary joint type involved in the connection between the humerus, radius, and ulna at the elbow. Similarly, a pivot joint permits rotational movement, but it does not connect these specific bones in the way a hinge does. Gliding joints, on the other hand, involve bones sliding over one another and do not provide the primary movement function seen at the elbow. Therefore, the hinge joint accurately represents the anatomical feature that connects these structures